1. Field of the Invention
This invention relates to an optical communication system, particularly to an improvement of modulation in optical communication systems utilizing a light emitting diode with linear relation of drive signal current vs. optical output power over a range that changes with signal frequency.
2. Description of the Prior Art
It is known that the relation between drive signal current and optical output power of a light emitting diode has a linear range that depends on signal frequency. When modulating light intensity in an optical communication system utilizing a light emitting diode, this non-linear characteristic does not cause any problems for digital signals, but has the disadvantage for analog signals that the output signal waveform is distorted to generally preclude a more desirable degree of modulation without such distortion.